<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>indentString</title>
</head>
<body>
    <div id="content"></div>
    <script>
        const indentString = (str,count,indent = ' ') => str.replace(/^/gm,indent.repeat(count));
        document.getElementById('content').innerHTML = indentString('Lorem\nIpsum', 2) + '<br />' + indentString('Lorem\nIpsum', 2, '_');
    </script>
</body>
</html>